Plasma emission diagnostics during fast deposition of microcrystalline silicon thin films in matrix distributed electron cyclotron resonance plasma CVD system

The structural and optoelectronic properties of undoped hydrogenated microcrystalline silicon (μc-Si:H) films deposited in a matrix distributed electron cyclotron resonance (MDECR) plasma CVD system using pure silane were studied as a function of microwave power (P_MW) and gas pressure (P_gas). The analysis of the silane plasma optical emission spectra (OES) shows the effect of the deposition conditions on the plasma chemistry and resulting film microstructure as studied by spectroscopic ellipsometry and atomic force microscopy. The use of the P_MW and P_gas as tunable parameters to achieve μc-Si:H films with desired microstructure is discussed. Intrinsic μc-Si:H films with good phototransport properties were realized at high deposition rate. Our study shows the usefulness of OES as a fast diagnostic tool for controlling and optimizing the μc-Si:H deposition process in MDECR reactor.